A tree can be added into a sheet. To do so, there are two steps which must be done. First, the `value` attribute of the sheet must refer to a method, which return a tree instead of a list. Second, to display the tree, use the `<tc:columnNode/>` tag.

Tag Library Documentation: |

There is a tree in the first column. You can expand and collapse the items. The `<tc:columnNode/>` tag can contain several tags for a tree. In this example, it's a `<tc:treeIndent/>` to intent the single entries of the tree.

<tc:sheet value="\#{sheetTreeController.solarTree}" var="solarObject" showRoot="true" showRootJunction="true"> <tc:columnNode label="Name"> <tc:treeIndent/> <tc:out value="\#{solarObject.userObject.name}"/> ...